A new Irish study has revealed levels of genetic diversity in Irish populations that are greater than genetic diversity between the entire human race. 13 different varieties of brown trout in Lough Corrib had already been identified by Inland Fisheries Ireland.

‘’Thin and streamlined like a herring, croneen trout are a pelagic fish, designed to swim long distances to spawn. The croneen population in the Lough Derg catchment of the Shannon’s main stem retreat to the small Camcor river in Co Offaly, 50 kilometres away, to spawn.

Another trout variety in the river Suir, which hasn’t yet been named, was found to travel 78km from the river Nier in Co Waterford, where it is born, down to the main stem of the Suir’’.

The study, whch also characterized trout migrator movements also found that spawning in the eight mile Owen Brin river, one of the smallest Mask sub-catchments, supplied more than 40 per cent of the adult population of trout in the lake. This highlights the conservation value of such spawning areas and this pattern is repeated right across Ireland.

Ireland’s lakes support such fine Lough trout fisheries in part due to their cold temperatures which rarely exceed 20C in the summer. Among other things, this study highlights the importance of genetic diversity to Irelands trout populations; a characteristic that is likely to be instrumental in helping trout populations survive climate change (for further information on the impacts of stocking on trout genetic diversity, see the WTT’s stocking page by clicking here.)